Answer:
1. A model’s usefulness depends on the accuracy of its predictions.
2. Daniel Bernoulli
3. molecule
4. It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
5. Consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
Explanation:
The discovery that macroscopic and microscopic phenomena are connected took several hundred years.
A model is a representation of a real life system that serves as a tool for predictions and explanation. Since models serve a predictive purpose, a model’s usefulness depends on the accuracy of its predictions.
The pressure of a gas is caused by the collision of gas molecules with the walls of the container. This was established by the scientist called Daniel Bernoulli.
Avogadro was able to create the term molecule to describe a substance that has independent existence. The discovery that macroscopic and microscopic phenomena are connected took several hundred years. It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
The results of experiments investigating the relationship between microscopic and macroscopic phenomena affect a model of molecular theory in the sense that consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
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During the course of your experiment you have obtained the following data: mass of the hydrate: 1.973 g mass of the anhydrate: 1.196 g The formula of the anhydrous salt: CaCl2 Calculate the following: (round to correct the number of significant figures and include units as required). mass of water loss in . number of moles of anhydrous salt after heating, in moles number of moles of water lost, in moles • number of moles of water per mole of hydrate, in moles (round to the whole number) provide the formula of a hydrate Note: you will not be able to add the bscript and leave one space between ionic compound and water.
Answer:
See explanation
Explanation:
Mass of water lost = mass of hydrated salt - mass of anhydrous salt
Mass of water lost = 1.973 g - 1.196 g = 0.777g
Number of moles of water lost = 0.777g/18g/mol = 0.043 moles
Number of moles of anhydrous salt = 1.196 g /111g/mol = 0.011 moles
To obtain the number of moles of water of crystalization per hydrate molecule;
Number of moles of anhydrous salt = number of moles of hydrated salt
0.011 = 1.973 /111 + 18x
0.011(111 + 18x) = 1.973
1.221 + 0.198x = 1.973
0.198x = 1.973 - 1.221
x= 4
Hence, there are 4 moles of water per hydrate molecule. The formula of the hydrate is CaCl2.4H2O
Are the components of a solution fixed?
Answer:
yes
Explanation:
the components of solutions fixed
To prepare a standard (calibration) curve for a spectroscopy experiment, start by preparing ___________ with ______________ Then, measure the ______________ of each solution at _____________ and create a plot of ____________ for the measured values. Finally, find the best-fit line of the data set.
Answer: See explanation
Explanation:
The calibration curve is the method used for the determination of the concentration of a substance such that the unknown sample will be compared to some standard samples of the known concentration.
To prepare a standard (calibration) curve for a spectroscopy experiment, start by preparing (multiple solutions) with (different known concentrations). Then, measure the (absorbance) of each solution at (thesame wavelength) and create a plot of (absorbance vs. concentration) for the measured values. Finally, find the best-fit line of the data set.
If the concentration of products is increased the equilibrium is shifted from * left to right/ to the left/ right to left /down left
Answer:
to the left
Explanation:
If the concentration of products is increased for a reaction that is in equilibrium, the equilibrium would shift to the left side of the reaction (the reactant's side).
For a reaction that is in equilibrium, the reaction is balanced between the reactants and the products. According to Le Cha telier's principle, if one of the constraints capable of influencing the rate of reactions is applied to such a reaction that is in equilibrium, the equilibrium would shift so as to neutralize the effects created by the constraint.
Hence, in this case, if the concentration of the products of a reaction in equilibrium is increased, the equilibrium would shift in such a way that more reactants are formed so as to annul the effects created by the increase in the concentration of the products. Since reactants are always on the left side of chemical equations, it thus means that the equilibrium would shift to the left.
A functional group introduces heteroatoms into a carbon chain to increase
polarity.
chain length.
molecular mass.
reactivity.
Answer:
reactivaty
Explanation:
here you go for the answer
What is the molecular formula of following show how it is done.1 nitric acid 2 Sulphuric acid 3 Methane 4 Potassium oxide 5 Silver chloride 6 Limestone . Answer it ASAP.Thank u
Answer:
1.HNO₃
Nitric acid is a nitrogen oxoacid of formula HNO3 in which the nitrogen atom is bonded to a hydroxy group and by equivalent bonds to the remaining two oxygen atoms.
2.H₂SO₄
3.CH₄
Methane (US: , UK: ) is a chemical compound with the chemical formula CH4 (one atom of carbon and four atoms of hydrogen). It is a group-14 hydride and the simplest alkane and is the main constituent of natural gas.
4.K₂O
5.AgCl
6.CaCO3
Limestone consists of calcium carbonate, which has the chemical formula CaCO3. Limestone exists in sedimentary and crystalline form.
Explanation:
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Aqueous hydrochloric acid HCl will react with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O. Suppose 20. g of hydrochloric acid is mixed with 7.56 g of sodium hydroxide. Calculate the minimum mass of hydrochloric acid that could be left over by the chemical reaction. Round your answer to 2 significant digits.
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Which one of these statements is/are true: I. All redox reactions with positive emfs are spontaneous. II. If a redox reaction is spontaneous, it must be fast. III. A spontaneous redox reaction will have a cathode reaction that has a more negative reduction potential than the anode. III only. I and III are true. I only. II only. All of I, II, and III are true.
Answer:
yea all the answers are true
Redox reaction is the transfer of the electron from one species to another. All of the three statements are true about the redox reaction.
What is a redox reaction?A redox reaction is a type of chemical reaction in which the electrons are gained and lost by a species. The positive EMF of the cell results in spontaneous and will move the reaction in the forward direction.
In a redox reaction, the cathode reaction is comparatively more negative than the reduction potential present at the anode.
Therefore, option E. All I, II, and III are true.
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How is the rate of a reaction affected when the temperature increases?
A. The rate decreases because the reactant particles move too
quickly to react.
B. The rate increases because the equilibrium constant increases.
C. The rate increases because the reactant particles collide more
often.
D. The rate decreases because the products reform the reactants more quickly
more quickly.
The rate of reaction increases when the temperature increases because the reactant particles collide more often and the correct option is option C.
What is Rate of reaction?
The rate of reaction refers to the speed at which the products are formed from the reactants in a chemical reaction. It gives some insight into the time frame under which a reaction can be completed.
The rate or speed of reaction can be defined as the change in the concentration of any one of the reactants or products per unit time.
The rate is higher at higher temperatures because colliding particles will have the required activation energy at high temperature and more successful collisions will take place.
Therefore, The rate of reaction increases when the temperature increases because the reactant particles collide more often and the correct option is option C.
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12.39 HBr can be added to alkenes in either the absence or presence of peroxides (producing either the Markovnikov or the anti-Markovnikov addition product). What intermediates leading to the formation of the major product are observed when 1-butene is treated with 1) HBr or 2) HBr/peroxides
Answer:
See explanation and image attached
Explanation:
The reaction of HBr with 1-butene is an addition reaction. The HBr adds across the double bond to yield a saturated halogenoalkane.
In the absence of peroxides, the reaction proceeds in accordance with Markovnikov rule which states that;''the negative part of the addendum, is attached to the carbon atom with the least number of hydrogen atoms attached.'' This occurs in the first reaction shown in the image.
In the presence of peroxides, the reaction proceeds in an anti-Markovnikov manner to yield the product shown in the second reaction.
A reaction vessel for synthesizing ammonia by reacting nitrogen and hydrogen is charged with 6.54 kg of H2 and excess N2. A total of 30.4 kg of NH3 are produced. What is the percent yield of the reaction
Explanation:
The given data is:
The mass of hydrogen is 6.54 kg.
The actual yield is 30.4 kg.
The balanced chemical equation of the reaction is:
[tex]N_2(g)+3H_2(g)<=>2NH_3(g)[/tex]
At first the theoretical yield should be calculated by using the balanced chemical equation:
3 mol. of hydrogen forms ---- 2 mol. of ammonia.
The molar mass of hydrogen is 2.0 g/mol.
The molar mass of ammonia is 17.0 g/mol.
Hence, the above statement can be rewritten as:
6g of hydrogen forms --- 34g of ammonia.
Then,
6.54g of hydrogen forms :
[tex]6.54 kg x 34 g / 6 g\\=37.1 kg[/tex]
% yield = (actual yield /theoretical yield )x 100
=(30.4 kg /37.1 kg )x100
=81.9
Hence, % yield is 81.9.
Standard hydrogen electrode acts as both anode and cathode.Explain.
Answer:
A Standard Hydrogen Electrode is an electrode that scientists use for reference on all half-cell potential reactions. The value of the standard electrode potential is zero, which forms the basis one needs to calculate cell potentials using different electrodes or different concentrations. It is important to have this common reference electrode, just as it is important for the International Bureau of Weights and Measures to keep a sealed piece of metal that is used to reference the S.I. Kilogram.
Answer:
The role of an electrode as cathode or anode depends on the nature and electrode potential of the other electrode with which it forms the complete electrochemical cell.
When a cell is to be made with zinc electrode and hydrogen electrode, the hydrogen electrode will behave as a cathode and the zinc electrode will behave as anode because zinc is present above hydrogen in the activity series. That is zinc is more electropositive than hydrogen.
If the cell is made with a copper electrode and hydrogen electrode, the hydrogen electrode will behave as anode and the copper electrode as a cathode. This is due to the fact that Cooper is present below hydrogen in the activity series. Copper is less electropositive than hydrogen.
Explanation:
Decide which of the following statements are true and which are false.
True False: Real gas molecules behave most ideally at low temperature and high pressure.
True False: Ideal gas molecules have small volumes and exert weak attractive forces on one another.
True False: At constant temperature, the heavier the gas molecules, the smaller the average velocity.
True False: In order for two separate 1.0 L samples of O2(g) and H2(g) to have the same average velocity, the O2(g) sample must be at a lower temperature than the H
2(g) sample.
True False: At constant temperature, the heavier the gas molecules, the larger the average kinetic energy.
True False: As temperature decreases, the average kinetic energy of a sample of gas molecules decreases.
Answer:
False
True
True
False
False
True
Explanation:
Ideal behavior of gases is observed at high temperature and low pressure when the gas molecules are isolated from each other.
According to the kinetic theory of gases, gases occupy negligible volume and do not exert significant attractive forces on each other.
The average velocity of gases at constant temperature depends on molecular mass. Heavier molecules possess smaller average velocity than lighter molecules at constant temperature.
At constant temperature, molecules of different gases have the same average kinetic energy but different average velocities since they have different molecular masses. So, the average kinetic energy of gas molecules only depends on temperature.
Prepare a flow sheet for the preparation of triphenylmethanol. Using your knowledge of the physical properties of the solvents, reactants, and products, show how the products can be purified. Indicate which layer should contain the product in the liquid/liquid extraction steps.
Answer:
See explanation and Image attached
Explanation:
The preparation of triphenylmethanol occurs as shown in the image attached to this answer.
The first step is the nucleophillic reaction of the phenyl magnesium bromide with the carbonyl group.
Reaction of the second molecule of phenyl magnesium bromide with the product yields triphenyl methoxide ion. Reaction with acid yields the triphenylmethanol product which is extracted into the organic phase.
The triphenylmethanol product can be purified by recrystallization.
The solubility of lithium fluoride, LiF, is 1.6 g/L, or 6.2 x 10â2 M.
a. Write the balanced solubility equilibrium equation for LiF.
b. Determine the molar concentration of the lithium ion and the fluoride ion.
c. Write the Ksp expression for the reaction.
d. Calculate Ksp for lithium fluoride.
Answer:
a. LiF(s) ⇄ Li⁺(aq) + F⁻(aq)
b. [Li⁺] = [F⁻] = 6.2 x 10⁻² M
c. Ksp = [Li⁺] [F⁻]
d. Ksp = 3.8 × 10⁻³
Explanation:
The solubility (S) of lithium fluoride, LiF, is 1.6 g/L, or 6.2 x 10⁻² M.
a. The balanced solubility equilibrium equation for LiF is:
LiF(s) ⇄ Li⁺(aq) + F⁻(aq)
b. We will make an ICE chart.
LiF(s) ⇄ Li⁺(aq) + F⁻(aq)
I 0 0
C +S +S
E S S
Then, [Li⁺] = [F⁻] = S = 6.2 x 10⁻² M
c. The solubility product constant, Ksp, is the equilibrium constant for a solid substance dissolving in an aqueous solution.
Ksp = [Li⁺] [F⁻]
d.
Ksp = [Li⁺] [F⁻] = (6.2 x 10⁻²)² = 3.8 × 10⁻³
Identify the element for each of these electron configurations. Then determine whether this configuration is the ground state or an excited state.
a. 1s2 2s2 2p6 3s2 3p6 4s2 3d 9
b. 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f 14 5d7
Answer:
a. 1s2 2s2 2p6 3s2 3p6 4s2 3d 9 - the element is zinc and this is an excited state configuration
b. 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f 14 5d7 -the element is iridium and this is a ground state configuration
Explanation:
The ground state is the lowest energy state of an atom while excite states of Zn atom are higher energy states.
The configuration, 1s2 2s2 2p6 3s2 3p6 4s2 3d 9 applies to zinc atom in excited state while the configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f 14 5d7 applies to iridium atom in ground state.
QUESTION 11
Identify the reaction type.
KOH + HNO3 -> H2O + KNO3
O combustion
O decomposition
O combination
O single displacement
O double displacement
1)Consider the reactions observed when NaOH(aq) and NH3(aq) were added to the solutions containing Zn2 (aq): a)What is the identity of the precipitate formed when the NaOH(aq) and NH3(aq) were added dropwise (limited amounts added)
Answer:
A white gelatinous precipitate is observed in each case.
Explanation:
Qualitative analysis in chemistry is mostly used to identify the ions present in a sample by adding certain reagents. The observation after adding the reagent often leads to an inference.
When NaOH is added to a solution containing Zn^2+ in drops, a white gelatinous precipitate is observed.
When NH3(aq) is added in drops to a solution containing Zn^2+, a white gelatinous precipitate is also observed.
Identify the true statements regarding hydrogen bonding. Select all that apply. Group of answer choices Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom.
Answer:
True
Explanation:
Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative element such as N, O, or F.
Hydrogen bonding affects several physical properties of molecules in which it occur. For example, the high boiling point of water is caused by intermolecular hydrogen bonding irrespective of the low relative molecular mass of water.
The statement stating the presence of hydrogen bonding between the hydrogen and N, O, and F has been true.
Hydrogen bonding has resulted when the electrostatic interaction has been found in the atoms that have been more electronegative than the Hydrogen atoms.
The electrostatic force helps in attracting the atoms towards the hydrogen and thereby the hydrogen bonding takes place. It has been a weak force present in the molecules. The hydrogen bonding can be easily breakable.
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Carboxylic acids and alcohols react via dehydration and condensation to produce a/an _______ and water.
Question options:
amine
ether
polymer
ester
Answer:
ester
Explanation:
Carboxylic acids and alcohols react in the presence of strong acid to produce an ester and water. The two carbon chains come together, which is the condensation, and then water is generated, which is dehydration. The resulting compound is an ester.
A sample of neon gas occupies 105 L at 27°C under a pressure of
985 torr. What volume would it occupy at standard condition
Answer: Volume occupied by given neon sample at standard condition is 123.84 L.
Explanation:
Given: [tex]V_{1}[/tex] = 105 L, [tex]T_{1} = 27^{o}C = (27 + 273) K = 300 K[/tex], [tex]P_{1}[/tex] = 985 torr
At standard conditions,
[tex]T_{2}[/tex] = 273 K, [tex]P_{2}[/tex] = 760 K, [tex]V_{2}[/tex] = ?
Formula used to calculate the volume is as follows.
[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}\\\frac{985 torr \times 105 L}{300 K} = \frac{760 torr \times V_{2}}{273 K}\\V_{2} = \frac{94116.75}{760} L\\= 123.84 L[/tex]
Thus, we can conclude that volume occupied by given neon sample at standard condition is 123.84 L.
Question 4
18 g of carbon dioxide contains how many oxygen atoms?
Answer:
4.92×10²³ atoms of oxygen.
Explanation:
We'll begin by calculating the number of mole of oxygen in 1 mole of CO₂. This can be obtained as follow:
1 mole of CO₂ contains 2 mole of oxygen.
1 mole of CO₂ = 12 + (2×16)
= 12 + 32
= 44 g
Thus,
44 g of CO₂ contains 2 moles of oxygen.
Next, we shall determine the number of mole of oxygen in 18 g of CO₂. This can be obtained as follow:
44 g of CO₂ contains 2 moles of oxygen.
Therefore, 18 g of CO₂ will contain
= (18 × 2)/ 44 = 0.818 mole of oxygen.
Finally, we shall determine the number of atoms in 0.818 mole of oxygen. This can be obtained as follow:
From Avogadro's hypothesis,
1 mole = 6.02×10²³ atoms.
Therefore,
0.818 mole = 0.818 × 6.02×10²³ atoms.
0.818 mole of oxygen = 4.92×10²³ atoms.
Thus, 18 g of CO₂ contains 4.92×10²³ atoms of oxygen.
What is the formula for manganese (IV) oxide?
A. MnO4
B. Mn40
C. MNO2
D. Mn20
The formula of manganese (IV) oxide is MNO2
The formula for manganese (IV) oxide is [tex]MnO_4[/tex]. Therefore, the correct option is A.
A manganese atom is bonded to four oxygen atoms to produce an inorganic compound known as manganese(IV) oxide with the chemical formula [tex]MnO_4[/tex]. It is often referred to as manganese dioxide. The +4 oxidation state of a manganese compound is indicated by the Roman numeral "IV" in the name.
Pyrolusite, a naturally occurring mineral, is a dark brown or black solid consisting of manganese(IV) oxide. Due to its favorable properties, it is often employed in a wide variety of applications. It acts as a catalyst, especially when breaking down hydrogen peroxide. Additionally, it is used to make batteries, ceramics, glass and pigments.
Therefore, the correct option is A.
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Determine the rate of reaction based on the data below:
75-
rate of reaction = y
hydrogen produced (cm)
х
y
25
50
75
100
125
time (seconds)
Answer:
75
Explanation:
is the answer for your question
Tapeworm is grouped in the phylum Platyhelminthes
Answer:
Tapeworm, also called cestode, any member of the invertebrate class Cestoda (phylum Platyhelminthes), a group of parasitic flatworms containing about 5,000 species. ... Tapeworms also lack a circulatory system and an organ specialized for gas exchange.
3 why does soldium produce blue colour when dissolve in ammonia?
Answer:
Because it is dissolving and has pigment.
Explanation:
Answer:
The solvated electron is responsible for a great deal of radiation chemistry. Alkali metals dissolve in liquid ammonia giving deep blue solutions which conduct electricity . The blue colour of the solution is due to ammoniated electrons which absorb energy in the visible region of light.
Determine the number of moles of aluminum in 2.154 x 10-1 kg of Al. Group of answer choices 5816 mol 7.984 mol 6.02 X 1023 mol 4.801 mol 8.783
Answer:
Avogadro's number is 1 mol = 6.02 * 10^23 elements
It means that 1 mol of atoms is 6.02 * 10^23 atoms
1 mol of atoms = 6.02 * 10^23 atoms
From there, if you divide both sides by 1 mol of atoms, you get
1 = 6.02 * 10^23 atoms / 1 mol of atoms.
That means, that to pass from a number of moles of atoms to number of atoms you have to multipby by the conversion factor
6.02*10^23 atoms Al/ 1 mol Al
That is the second option of the list.
Explanation:
the nutrition label on rice lists the amounts of protein, carbohydrates and fats in one serving. these substances are important for human nutrition
Answer:
Carbohydrates, proteins, and fats are biological macromolecules that are made up of chemical elements which are inherent to chemistry.
Chemistry explain how these macromolecules are bonded together at the molecular level and give an explanation for their behavior.
Explanation:
what is the complete ionic equation between the reaction of sodium carbonate and calcium hydroxide to form a precipitate
Answer:
CaCl2(aq) + Na2CO3(aq) → CaCO3(s) + 2NaCl(aq)
Reference:
H.W. Hanna and A. Dittmar; Laboratory Manual for General Chemistry, 4th ed.; Morton Publishing Company, Denver, Colorado
A sample of gas occupies 12 L under a pressure of 1.2 atm. What
would its volume be if the pressure were increased to 3.6 atm?
(assume temp is constant)
Explanation:
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